1. Field of the Invention
The present invention relates generally to an image processing system, and more particularly, to an apparatus and method for reconfiguring an image processing system to bypass hardware, which may, for example, be faulty.
2. Field of the Related Art
In a conventional Recirculate Document Handler (RDH), a set of original documents are repeatedly read by an automatic image reader, and a required number of copies of the set of documents are produced. When the number of copies is large, the amount of mechanical handlings of the original documents is large, resulting in the possibility of damaged documents. In a proposed electronic RDH, a required number of copies are produced by reading in a proposed the image read only once. In the electronic RDH a data storage unit stores the read image data. It is desirable that the memory capacity of the storage unit be large. For this reason, a magnetic memory device, such as a hard disk, is preferred; although, a semiconductor memory may be used. To output a necessary number of copies, a set of original documents is read one time in the page order, and the read image data is stored into the storage unit. The image data stored is repeatedly read out of the storage unit in the page order, and transferred to the image output terminal, thereby producing a designated number of copies.
Since the image data contains an extremely large amount of information, the memory capacity of the storage unit must be extremely large in order to store the image information of multiple original documents. To alleviate the large storage requirements, the image data is applied to a compressor before storing compressed data in the storage unit, thereby conserving space in the storage unit. When the compressed data read is out of the storage unit, the compressed data is applied to a decompressor, which generates the data in its original uncompressed form. The uncompressed data is transferred to the image output terminal.
In the magnetic memory device, such as a hard disk, an average access time, including factors such as seek time, is approximately 1 M bytes/sec. A normal signal transfer time is 10 M bytes/sec. Thus, a speed gap exists between the access time and the transfer time. To address this speed gap problem, a page buffer is provided. The compressed data from the compressor is temporarily stored into the page buffer every page. After the storage of the image data into the hard disk is complete, the data is read out of the hard disk into the page buffer every page and then applied to the decompressor. The decompressed image data is transferred to the image output terminal.
In the image processing system described above, when there is a fault in one of either the compressor, page buffer, disk, or decompressor, the system becomes inoperable, even when the remaining components do not have faults.